岩層參數變異特性對邊坡楔型破壞機率影響之研究

Influence of Failure Probability Due to Parameter Variance Characteristics for Rock Wedge Slope

紀雲曜(Yun-Yao Chi) ； 李雅芬(Ya-Fen Lee)

《中國土木水利工程學刊》 24卷2期 (2012/06) Pp. 111-119

https://doi.org/10.6652/JoCICHE.201206_24(2).0002

摘要

本文以邊坡楔型破壞為例，首先利用可靠度指標的搜尋方法，求得四種破壞模式的破壞機率，再經由案例邊坡岩層參數變異特性的改變，以分析結果探討岩層參數變異特性對邊坡楔型破壞機率之影響。本文結果顯示：（1）總破壞機率與中心安全係數（central factor of safety, CFS）呈良好之函數關係：（2）破壞面之強度參數，凝聚力（c）的變異對破壞機率的影響，大於磨擦角（φ）的變異對破壞機率的影響：（3）考慮地下水壓參數（Gw），只有相關係數p（c,φ）存在時，或p（Gw,φ）與p（c,φ）同時存在時，隨者p絕對值的增加，破壞機率均減小；當只有p（Gw,φ）存在時，p（Gw,φ）絕對值的增加，破壞機率會增加。

關鍵字

楔型邊坡 ； 可靠度指標 ； 破壞機率 ； 參數 ； 變異

並列摘要

Slope failure is a complex geological/geotechnical problem that involves much uncertainty. In this paper, failure probability of rock wedge slope is developed, considering the parameter uncertainties, by an optimum searching technical for the reliability index and based on the analysis of safety for four failure modes of rock wedge slope. With this approach, the influences of failure probability due to parameter uncertainties are presented via the results of the case slope under different parameter variance scenario. The results include: (1) there is a good function relationship of central factor of safety (CFS) and failure probability; (2) the influence of variance of cohesion (c) for failure probability is more than the one of the friction angle (φ) for failure probability; (3) considering underground water pressure (Gw), failure probabilities decrease with the absolute of correlation coefficient increased under only p(c, φ) or both p(Gw, φ) and p(c, φ) existed conditions.

並列關鍵字

rock wedge slope ； reliability index ； failure probability ； parameter ； Uncertainty